Influence of void fraction and filling ratio on heat transfer characteristics of a packing bed thermosyphon (PBTP)

Abstract

This research aims to study the influence of void fraction and filling ratio on heat transfer characteristics of a Packing Bed Thermosyphon (PBTP). The PBTP made of copper tube with an inner diameter of 7.5 mm and length of 100 mm. The metal wool inside the tube was made of stainless steel with a thickness of 0.05 mm and width of 0.5 mm, taken as void fraction of 0.925, 0.95 and 0.975. The selected working fluid was ethanol with a filling ratio of 30, 50 and 70 % volume of evaporator with an inclination angle of 90 o . The results found that the maximum heat flux occurred with a filling ratio of 50 % volume of evaporator with void fraction of 0.975. When compared to the heat flux values of the PBTP and convention Thermosyphon (CVTP). At a filling ratio of 50 % volume of evaporator the heat flux of the PBTP was higher than the CVTP. On the other hand, at a filling ratio of 30 and 70 % volume of evaporator the heat flux of the CVTP was higher than the PBTP.